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The emergence of quantum capacitance in epitaxial graphene

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posted on 2016-06-21, 14:01 authored by Amira Ben Gouider Trabelsi, Feodor Kusmartsev, Derek Michael Forrester, Olga Kusmartseva, Marat Gaifullin, Patricia Cropper, M. Oueslati
We found an intrinsic redistribution of charge arises between epitaxial graphene, which has intrinsically n-type doping, and an undoped substrate. In particular, we studied in detail epitaxial graphene layers thermally elaborated on C-terminated 4H-SiC( 4H-SiC(000-1)). We have investigated the charge distribution in graphene-substrate systems using Raman spectroscopy. The influence of the substrate plasmons on the longitudinal optical phonons of the SiC substrates has been detected. The associated charge redistribution reveals the formation of a capacitance between the graphene and the substrate. Thus, we give for the first time direct evidence that the excess negative charge in epitaxial monolayer graphene could be self-compensated by the SiC substrate without initial doping. This induced a previously unseen redistribution of the charge-carrier density at the substrate-graphene interface. There a quantum capacitor appears, without resorting to any intentional external doping, as is fundamentally required for epitaxial graphene. Although we have determined the electric field existing inside the capacitor and revealed the presence of a minigap (≈4.3meV) for epitaxial graphene on 4H-SiC face terminated carbon, it remains small in comparison to that obtained for graphene on face terminated Si. The fundamental electronic properties found here in graphene on SiC substrates may be important for developing the next generation of quantum technologies and electronic/plasmonic devices.

History

School

  • Science

Department

  • Physics

Published in

Journal of Materials Chemistry C

Citation

BEN GOUIDER TRABELSI, A., 2016. The emergence of quantum capacitance in epitaxial graphene. Journal of Materials Chemistry C, 4, 5829.

Publisher

© Royal Society of Chemistry

Version

  • AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

2016-05-27

Publication date

2016

Notes

This paper was accepted for publication in the journal Journal of Materials Chemistry C and the definitive published version is available at http://dx.doi.org/10.1039/C6TC02048H.

ISSN

2050-7526

Language

  • en

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